Cant forward pictures in attachments

Hai friends,
Iam using zimbra 5 version on my server.The interface is very easy and user friendly.But iam facing one problem in this version.When I forward any mail received to my address to any other addresses, the picture files included in the received email is not attached with the sending mail.Even though my received mail shows these attachments,it is not forwarded to the senders address.How can i solve these problem?
Did any one seen such problems??